Mechanical, cardiopulmanary resuscitators have been reported in the patent literature for over seventy years. In 1916, Pierpoint No. 1,197,232 disclosed an apparatus in which pressurized air, generated by a hand held bellows, is forced through a two way inhalation-exhalation valve, through a tube leading to a face mask and into the trahea and lungs of the distressed individual. Upon exhalation, air exhausts in the reverse direction through the two way valve. Pierpont's invention has served as a benchmark for manaul resuscitators for over the years. While refinements have been made, the basic precepts of Pierpoint's invention have remained largely intact.
Exemplary of such a refinement was Adam's Pat. No. 3,196,866 resuscitator, which recognized the need for a two way valve that would normally stay open, therein obviating the need for repetitive pumping of the bellows once breathing was restarted. Additionally, the hand operated bellows was replaced with a self-distending football shaped elastic bag that was lightweight, portable and reportedly required only one hand to compress.
Flynn Pat. No. 4,532,923 described an improved resuscitator bag that has a ribbed football shape. He contends in his patent that thin walled bags, those which can be compressed with one hand, do not recover to their normal shape fast enough especially in emergency situations, and this precipitates anxiety in the operators as they find it very difficult to jude how much air has been forced into the distressed individual's lungs. As a consequence of this uncertainly the operators often over compensate, which results in a tendency to over pressurize the lungs. Flynn proposed that a thicker, ribbed, rapidily self-inflating bag will aleviate most of those concerns, and the operator will be less likely to over compensate.
The applicant's own experience reinforces the necessity for a fast recovering bag, however, this feature has to be tempered with the recognition that the operator's hands will quickly tire compressing a stiff bag. As a consequence the operator will become less effective at rendering other emergency procedures requiring manual dexterity, such as ensuring that the throat passage is clear, holding up the jaw and adjusting the face mask. Under certain circumstances there is the need for the freedom to be able to use both hands.
Additionally, with increasing costs for skilled medical labor and a growing concern about the accidental transmission of virulent contagious diseases, more and more respiractory technologists are recognizing the benefits of disposable equipment. There is no chance of cross-contamination and lengthy cleaning procedures are eliminated.